It may also be a case that the instructor didn't really say too much, and just tried to be encouraging.
I suspect A/d said to his instructor that he didn't consider a g/a an option, and as the instructor saw that he was pretty shock up, didn't want to critise. The instructor could have been thinking that the what went wrong and how to get out of it chat, was best left until the next lesson when he could demonstrate it again, and a/d was a bit more relaxed. In my opinion that would be a good call....certainly would have been more effective teaching method if the same had happened to me in my training.
Sometimes we say something to an instructor, and just because they don't disagree there an then, we tend to assume that they are agreeing with us.
Don't be too hard on this instructor, he may have done the best thing.